Devices with movable components may experience degradation, efficiency losses, and shortened service life due to component wear. For example, engine components and energy conversion devices such as hydraulic pumps and hydraulic motors often include gears, bearings, and other movable components which translate and/or rotate with respect to a countersurface. After many operation cycles, friction between such movable components and the countersurface may cause degradation, i.e., wear, of the movable component.
Harder components generally experience less wear than comparatively softer components. Therefore, to minimize wear, a wear-reducing coating having an increased hardness, such as TiN, TiAlN, and CrN, may be applied to the movable components. However, such increased hardness may in turn damage the countersurface. That is, the increased hardness may actually increase friction between the movable component and the countersurface because of micro-cutting and abrasive three-body wear, and consequently degrade the countersurface. To compensate for such friction, a friction-reducing coating such as diamond-like carbon, rather than a wear-reducing coating, may be applied to the movable components. However, such friction-reducing coatings often suffer from decreased hardness and the aforementioned shortcomings.